Recently, I’ve been trying to setup dovecot with postfix on a server. While attempting to get kerberos/ldap authentication working, I’ve ran into the following error:

dovecot: Feb 22 22:43:02 Error: IMAP(leo): fcntl() failed with file /home/leo/Maildir/dovecot.index.log: No locks available
dovecot: Feb 22 22:43:02 Error: IMAP(leo): mail_index_wait_lock_fd() failed with file /home/leo/Maildir/dovecot.index.log: No locks available

The /home directory is a automounted NFS share from a remote server. To resolve this issue, ensure that nfslock is running on both the server and client machine.

Using putty with programs that bind keys to CTRL-S may be slighly problematic since putty will send XOFF, which will basically freeze your terminal until you send XON (CTRL-Q).

To disable XOFF, add to your .bashrc file the following lines:

stty ixany
stty ixoff -ixon
stty stop undef
stty start undef

Hit Shift + D, then enter ~s .* to delete all messages in your inbox.